Butter the sides and bottom of a 3 qt (9x13) baking dish. Preheat the oven to 350º.

In a large saucepan melt the butter over medium heat. Add the onions and peppers and cook until softened, about 10 minutes. Add the garlic and cook for another 2 minutes. Add the flour, chili powder, oregano, and cumin and cook for 1 minute. Add the chicken broth and stir to thicken the sauce. Reduce the heat to a simmer and add the milk and Ro-Tel. Cover the saucepan and simmer for 15-20 minutes stirring occasionally. Remove the pan from the heat and stir in the sour cream and the juice of 1/2 a lime. Season to taste with salt and pepper.

Cut each tortilla in half for easy assembly in baking pan. Ladle 1 cup of the sauce onto the bottom of the pan. Layer half the tortillas on top of the sauce cut sides facing out (a few will go in the center to cover any holes). Add half of the chicken, half of the remaining sauce, half of the cilantro and half of the grated cheese blend. Repeat the layering of tortillas, chicken, sauce, cilantro and finish with the remaining cheese.

Cook uncovered for 30-45 minutes or until brown and bubbling. Let stand 10 minutes before serving Serve with a good hot sauce like Cholulua. Enjoy!